The present invention relates to a traversing microtome and more especially to a traversing microtome having a blade holder adjustably mounted on a base for an adjustable blade and having a carriage which is supported displaceably on guide rails with respect to the base for carrying out the cutting movement and which carries an object holder.
Traversing microtomes of this general type are known, in which the carriage has flanges on its bottom side by which it is guided along slide rails on a support or base. Because the mode of guiding the carriage is of essential importance for the quality of cuts, the production of such bearings requires a high degree of precision. In spite of this, the force to be exerted in moving the carriage is often appreciable, resulting in nonuniform moving velocities of the carriage and thus in cuts of lesser quality. Also, the maintenance of wearing parts and the lubrication of the slide bearings require a relatively great expense. The scratching of the guide rails by dust particles contained in the lubricant must be prevented, together with soiling by a mixture of lubricants, cutting residues and embedding material.
A microtome is known from DE-OS No. 1,925,364 having a carriage which is guided on round rods by means of spherical bearings. constant maintenance is not required here as the guides are provided with permanent lubrication. The latter is made vacuum tight in a manner not described in detail and, consequently, is expensive. The force applied to move the carriage is small in this case, as rolling friction is used in place of sliding friction. However, a relatively large force is needed to brake the carriage.